Rtf.Dropper.Agent-9965975-1 — Office (OOXML) / .DOCX malware analysis

Static analysis result for SHA-256 6add2b3debc6d25b…

MALICIOUS

Office (OOXML) / .DOCX

484.3 KB
MD5: 666920c3d9edc2fc0f0985d0c697ed25 SHA-1: c31d9702bd60e5f02a28ec612cdce18193d8fed3 SHA-256: 6add2b3debc6d25b93aada0a315784790dcbf0eea7b03fdff2846bb634945cbf
502 Risk Score

Malware Insights

Rtf.Dropper.Agent-9965975-1 · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample utilizes an OOXML altChunk to import an RTF document which contains an embedded OLE object exploiting CVE-2017-11882 via the Equation Editor. This exploit is designed to download and execute a secondary payload, as indicated by the ClamAV detection name Rtf.Dropper.Agent-9965975-1. The presence of RTF_MZ_HEX and RTF_EQUATION_EDITOR heuristics strongly suggests the embedded object is a PE executable.

Heuristics 12

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    (in altChunk RTF word/Dominica.rtf) RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    (in altChunk RTF word/Dominica.rtf) RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • altChunk imports embedded RTF (RTF injection) critical OOXML_ALTCHUNK_RTF
    Document inlines an embedded RTF via an aFChunk relationship and a <w:altChunk> body element. This is the canonical RTF-injection wrapper used to smuggle RTF exploits (Equation Editor / URL Moniker / objdata) past DOCX-only scanners. Word opens the wrapper and executes the RTF inline. Recursing into the RTF for the exact exploit primitive.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    (in altChunk RTF word/Dominica.rtf) RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    (in altChunk RTF word/Dominica.rtf) Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • altChunk RTF auto-updates embedded executable object critical OOXML_ALTCHUNK_RTF_AUTOUPDATE_PE
    OOXML document imports an embedded RTF through altChunk; the RTF contains OLE object data, forces object update, and carries a hex-encoded PE payload. This is a stronger compound exploit-loader shape than a generic altChunk RTF wrapper, but it is not tied to a single CVE unless the nested RTF object primitive also matches one.
  • ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/Dominica.rtf) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    (in altChunk RTF word/Dominica.rtf) RTF contains ~2187KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Dominica.rtf) RTF contains 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Dominica.rtf) RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://opendope.org/xpaths
    • http://opendope.org/conditions
    • http://opendope.org/questions
    • http://opendope.org/components
    • http://opendope.org/SmartArt/DataHierarchy
    • http://ocsp.comodoca.com0
    • http://ocsp.sectigo.com0
    • http://ocsp.sectigo.com0D
    • http://ocsp.verisign.com0
    • http://ocsp.digicert.com0C
    • http://ocsp.digicert.com0A
    • http://ocsp.digicert.com0X
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/main
    • http://schemas.openxmlformats.org/schemaLibrary/2006/main
    • http://schemas.openxmlformats.org/drawingml/2006/chart
    • http://schemas.openxmlformats.org/drawingml/2006/chartDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/diagram
    • http://schemas.openxmlformats.org/drawingml/2006/picture
    • http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing
    • http://schemas.microsoft.com/office/drawing/2008/diagram
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliography
    • http://schemas.openxmlformats.org/drawingml/2006/compatibility
    • http://schemas.openxmlformats.org/drawingml/2006/lockedCanvas
    • http://crl.comodoca.com/AAACertificateServices.crl04
    • http://crl.sectigo.com/SectigoPublicCodeSigningRootR46.crl0{
    • http://crt.sectigo.com/SectigoPublicCodeSigningRootR46.p7c0#
    • https://sectigo.com/CPS0
    • http://crl.sectigo.com/SectigoPublicCodeSigningCAEVR36.crl0{
    • http://crt.sectigo.com/SectigoPublicCodeSigningCAEVR36.crt0#
    • https://www.globalsign.com/repository/0
    • http://ocsp.globalsign.com/ca/gstsacasha384g40C
    • http://secure.globalsign.com/cacert/gstsacasha384g4.crt0
    • http://crl.globalsign.com/ca/gstsacasha384g4.crl0
    • http://ocsp2.globalsign.com/rootr606
    • http://crl.globalsign.com/root-r6.crl0G
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/
    • https://www.verisign.com/rpa
    • http://csc3-2010-crl.verisign.com/CSC3-2010.crl0D
    • https://www.verisign.com/rpa0
    • http://csc3-2010-aia.verisign.com/CSC3-2010.cer0
    • http://cacerts.digicert.com/DigiCertAssuredIDRootCA.crt0E
    • http://crl3.digicert.com/DigiCertAssuredIDRootCA.crl0
    +7 more URL(s)

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003a12.bin
25c58b6da32ff90d0415dee2d75cd99af8d3511d7e7789fe6f65bef2967fd0d1
rtf-objdata-decoded RTF \objdata at offset 0x3A12 464881 bytes
objdata_01_off000e7da6.bin
cc308e6715adee10b4052e3519f5c9bbfb6bd9295fefbb1ca1819f74bb776a96
rtf-objdata-decoded RTF \objdata at offset 0xE7DA6 641618 bytes
objdata_02_off0022ca7c.bin
baa851e508de0c0fe3796025d004df72ceebc7132470d4cc307f31e2abe6c1fc
rtf-objdata-decoded RTF \objdata at offset 0x22CA7C 584266 bytes